Facile synthesis of crosslinked chitosan-tripolyphosphate/kaolin clay composite for decolourization and COD reduction of remazol brilliant blue R dye: Optimization by using response surface methodology

The facile synthesis of crosslinked chitosan-tripolyphosphate/kaolin clay (CS-TPP/KC) composite was performed by two subsequent steps involving modification of chitosan (CS) with an inorganic clay (kaolin, KC), followed by ionic cross-linking reaction by tripolyphosphat (TPP). The applicability of the CS-TPP/KC composite for decolourization and chemical oxygen demand (COD) reduction of remazol brilliant blue R dye (RBBR) from aquatic system was investigated. The main key factors that influences the RBBR dye decolourization and COD reduction such as A: CS-TPP/KC dosage (0.02 - 0.1 g), B: pH (4-10), and C: time (5 - 30 min) were optimized by using Box-Behnken design (BBD). The highest RBBR dye decolourization (99.5 %) and COD reduction (88.5 %) were observed at the following significant interactions: AB, BC, and AC (only on COD reduction was significant). Langmuir isotherm was the best model presented the adsorption process with remarkable adsorption capacity of 687.2 mg/g was obtained for CS-TPP/KC composite at 30 degrees C. This work highlights that CS-TPP/KC composite offers great potential as a low-cost and effective biocomposite material for the organic dyes removal and COD reduction from water/wastewater.